Steel Strapping is supplied with a zinc coating
or painted and waxed. Zinc increases corrosion resistance and waxing reduces strap friction to apply tension more evenly along its length. Steel is most commonly used for heavier materials such as brick and concrete products as it has a high tensile strength and minimal elongation under tension.
Steel strapping may be sealed with compressible metal seals or a crimping sealer, and requires heavy duty safety cutters.
Stainless steel strapping provides ultimate corrosion resistance but is more commonly used in process installation than for packaging.
The most common winding of steel strapping is Ribbon Wound where the strapping is wound on top of itself, the width of the coil is the same as the width of the strap, rather like a roll of tape. Oscillated or Mill Wound steel strapping is wound like a bobbin and contains much more strap and are usually 50kg in weight per coil.
Constructed from filaments embedded in polyester, composite strapping has good abrasion resistance and strength. It is increasingly used in place of steel as it is lighter in weight, corrosion proof and safer to use. Its excellent memory also enables it to securely hold flexing products such as timber without loss of tensionor damage to tyhe strapped product.
Composite polyester strapping is joined with a steel buckles and only requires a hand operated tensioning tool and light cutters, so is faster and more convenient than steel.
Parallel strands of hotmelt adhesive bonded polyester yarn make this a popular and economical choice for manual strapping and bale pressing of non-abrasive products such as paper and card. Softness and flexibility reduce the risk of damage to products and cartons.
Crosswoven strands of polyester yarn are coated with cold glue to improve the strap's rigidity and system strength. Woven offers higher resistance to chafing and shearing, where a small cut at the edge of the strap spreads across its width under tension, so are suited to use with rough edge consignments.
Oriented or tensalised polypropylene is the most versatile and widely used strapping, as it is compatible with manual and automatic systems. Compressible metal seals are used for manual strapping, but friction weld sealing is used for portable tensioner sealers and automatic systems as it is faster and cheaper.
Similar in construction and use to polypropylene, polyester tensalised strapping offers greater retained tension and recovery properties. This characteristic makes it a preferred choice for maintaining a secure hold where greater strain on the strapping is anticipated.
Polyester tensalised strapping is suitable for manual application and some friction weld systems.